/**********************************************************************
 *                          gost_pmeth.c                              *
 *             Copyright (c) 2005-2006 Cryptocom LTD                  *
 *         This file is distributed under the same license as OpenSSL *
 *                                                                    *
 *   Implementation of RFC 4357 (GOST R 34.10) Publick key method     *
 *       for OpenSSL                                                  *
 *          Requires OpenSSL 0.9.9 for compilation                    *
 **********************************************************************/
#include <openssl/evp.h>
#include <openssl/objects.h>
#include <openssl/ec.h>
#include <openssl/err.h>
#include <openssl/x509v3.h>     /* For string_to_hex */
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "gost_lcl.h"
#include "e_gost_err.h"
/* -----init, cleanup, copy - uniform for all algs  ---------------*/
/* Allocates new gost_pmeth_data structure and assigns it as data */
static int pkey_gost_init(EVP_PKEY_CTX *ctx)
{
    struct gost_pmeth_data *data;
    EVP_PKEY *pkey = EVP_PKEY_CTX_get0_pkey(ctx);

    data = OPENSSL_zalloc(sizeof(*data));
    if (!data)
        return 0;
    if (pkey && EVP_PKEY_get0(pkey)) {
        switch (EVP_PKEY_base_id(pkey)) {
        case NID_id_GostR3410_2001:
            data->sign_param_nid =
                EC_GROUP_get_curve_name(EC_KEY_get0_group
                                        (EVP_PKEY_get0((EVP_PKEY *)pkey)));
            break;
        default:
            return 0;
        }
    }
    EVP_PKEY_CTX_set_data(ctx, data);
    return 1;
}

/* Copies contents of gost_pmeth_data structure */
static int pkey_gost_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src)
{
    struct gost_pmeth_data *dst_data, *src_data;
    if (!pkey_gost_init(dst)) {
        return 0;
    }
    src_data = EVP_PKEY_CTX_get_data(src);
    dst_data = EVP_PKEY_CTX_get_data(dst);
    *dst_data = *src_data;
    if (src_data->shared_ukm) {
        dst_data->shared_ukm = NULL;
    }
    return 1;
}

/* Frees up gost_pmeth_data structure */
static void pkey_gost_cleanup(EVP_PKEY_CTX *ctx)
{
    struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(ctx);

    OPENSSL_free(data->shared_ukm);
    OPENSSL_free(data);
}

/* --------------------- control functions  ------------------------------*/
static int pkey_gost_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
{
    struct gost_pmeth_data *pctx =
        (struct gost_pmeth_data *)EVP_PKEY_CTX_get_data(ctx);
    switch (type) {
    case EVP_PKEY_CTRL_MD:
        {
            if (EVP_MD_type((const EVP_MD *)p2) != NID_id_GostR3411_94) {
                GOSTerr(GOST_F_PKEY_GOST_CTRL, GOST_R_INVALID_DIGEST_TYPE);
                return 0;
            }
            pctx->md = (EVP_MD *)p2;
            return 1;
        }

    case EVP_PKEY_CTRL_GET_MD:
        *(const EVP_MD **)p2 = pctx->md;
        return 1;

    case EVP_PKEY_CTRL_PKCS7_ENCRYPT:
    case EVP_PKEY_CTRL_PKCS7_DECRYPT:
    case EVP_PKEY_CTRL_PKCS7_SIGN:
    case EVP_PKEY_CTRL_DIGESTINIT:
#ifndef OPENSSL_NO_CMS
    case EVP_PKEY_CTRL_CMS_ENCRYPT:
    case EVP_PKEY_CTRL_CMS_DECRYPT:
    case EVP_PKEY_CTRL_CMS_SIGN:
#endif
        return 1;

    case EVP_PKEY_CTRL_GOST_PARAMSET:
        pctx->sign_param_nid = (int)p1;
        return 1;
    case EVP_PKEY_CTRL_SET_IV:
        pctx->shared_ukm = OPENSSL_malloc((int)p1);
        if (pctx->shared_ukm == NULL) {
            GOSTerr(GOST_F_PKEY_GOST_CTRL, ERR_R_MALLOC_FAILURE);
            return 0;
        }
        memcpy(pctx->shared_ukm, p2, (int)p1);
        return 1;
    case EVP_PKEY_CTRL_PEER_KEY:
        if (p1 == 0 || p1 == 1) /* call from EVP_PKEY_derive_set_peer */
            return 1;
        if (p1 == 2)            /* TLS: peer key used? */
            return pctx->peer_key_used;
        if (p1 == 3)            /* TLS: peer key used! */
            return (pctx->peer_key_used = 1);
        return -2;
    }
    return -2;
}

static int pkey_gost_ctrl01_str(EVP_PKEY_CTX *ctx,
                                const char *type, const char *value)
{
    int param_nid = 0;

    if (strcmp(type, param_ctrl_string) == 0) {
        if (!value) {
            return 0;
        }
        if (strlen(value) == 1) {
            switch (toupper((unsigned char)value[0])) {
            case 'A':
                param_nid = NID_id_GostR3410_2001_CryptoPro_A_ParamSet;
                break;
            case 'B':
                param_nid = NID_id_GostR3410_2001_CryptoPro_B_ParamSet;
                break;
            case 'C':
                param_nid = NID_id_GostR3410_2001_CryptoPro_C_ParamSet;
                break;
            case '0':
                param_nid = NID_id_GostR3410_2001_TestParamSet;
                break;
            default:
                return 0;
            }
        } else if ((strlen(value) == 2)
                   && (toupper((unsigned char)value[0]) == 'X')) {
            switch (toupper((unsigned char)value[1])) {
            case 'A':
                param_nid = NID_id_GostR3410_2001_CryptoPro_XchA_ParamSet;
                break;
            case 'B':
                param_nid = NID_id_GostR3410_2001_CryptoPro_XchB_ParamSet;
                break;
            default:
                return 0;
            }
        } else {
            R3410_2001_params *p = R3410_2001_paramset;
            param_nid = OBJ_txt2nid(value);
            if (param_nid == NID_undef) {
                return 0;
            }
            for (; p->nid != NID_undef; p++) {
                if (p->nid == param_nid)
                    break;
            }
            if (p->nid == NID_undef) {
                GOSTerr(GOST_F_PKEY_GOST_CTRL01_STR, GOST_R_INVALID_PARAMSET);
                return 0;
            }
        }

        return pkey_gost_ctrl(ctx, EVP_PKEY_CTRL_GOST_PARAMSET,
                              param_nid, NULL);
    }
    return -2;
}

/* --------------------- key generation  --------------------------------*/

static int pkey_gost_paramgen_init(EVP_PKEY_CTX *ctx)
{
    return 1;
}

static int pkey_gost01_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
{
    struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(ctx);
    EC_KEY *ec = NULL;

    if (data->sign_param_nid == NID_undef) {
        GOSTerr(GOST_F_PKEY_GOST01_PARAMGEN, GOST_R_NO_PARAMETERS_SET);
        return 0;
    }
    if (!ec)
        ec = EC_KEY_new();
    if (!fill_GOST2001_params(ec, data->sign_param_nid)) {
        EC_KEY_free(ec);
        return 0;
    }
    EVP_PKEY_assign(pkey, NID_id_GostR3410_2001, ec);
    return 1;
}

/* Generates GOST_R3410 2001 key and assigns it using specified type */
static int pkey_gost01cp_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
{
    EC_KEY *ec;
    if (!pkey_gost01_paramgen(ctx, pkey))
        return 0;
    ec = EVP_PKEY_get0(pkey);
    gost2001_keygen(ec);
    return 1;
}

/* ----------- sign callbacks --------------------------------------*/
/*
 * Packs signature according to Cryptopro rules
 * and frees up DSA_SIG structure
 */
int pack_sign_cp(DSA_SIG *s, int order, unsigned char *sig, size_t *siglen)
{
    *siglen = 2 * order;
    memset(sig, 0, *siglen);
    store_bignum(s->s, sig, order);
    store_bignum(s->r, sig + order, order);
    DSA_SIG_free(s);
    return 1;
}


static int pkey_gost01_cp_sign(EVP_PKEY_CTX *ctx, unsigned char *sig,
                               size_t *siglen, const unsigned char *tbs,
                               size_t tbs_len)
{
    DSA_SIG *unpacked_sig = NULL;
    EVP_PKEY *pkey = EVP_PKEY_CTX_get0_pkey(ctx);
    if (!siglen)
        return 0;
    if (!sig) {
        *siglen = 64;           /* better to check size of curve order */
        return 1;
    }
    unpacked_sig = gost2001_do_sign(tbs, tbs_len, EVP_PKEY_get0(pkey));
    if (!unpacked_sig) {
        return 0;
    }
    return pack_sign_cp(unpacked_sig, 32, sig, siglen);
}

/* ------------------- verify callbacks ---------------------------*/
/* Unpack signature according to cryptopro rules  */
DSA_SIG *unpack_cp_signature(const unsigned char *sig, size_t siglen)
{
    DSA_SIG *s;

    s = DSA_SIG_new();
    if (s == NULL) {
        GOSTerr(GOST_F_UNPACK_CP_SIGNATURE, ERR_R_MALLOC_FAILURE);
        return NULL;
    }
    s->s = BN_bin2bn(sig, siglen / 2, NULL);
    s->r = BN_bin2bn(sig + siglen / 2, siglen / 2, NULL);
    return s;
}


static int pkey_gost01_cp_verify(EVP_PKEY_CTX *ctx, const unsigned char *sig,
                                 size_t siglen, const unsigned char *tbs,
                                 size_t tbs_len)
{
    int ok = 0;
    EVP_PKEY *pub_key = EVP_PKEY_CTX_get0_pkey(ctx);
    DSA_SIG *s = unpack_cp_signature(sig, siglen);
    if (!s)
        return 0;
#ifdef DEBUG_SIGN
    fprintf(stderr, "R=");
    BN_print_fp(stderr, s->r);
    fprintf(stderr, "\nS=");
    BN_print_fp(stderr, s->s);
    fprintf(stderr, "\n");
#endif
    if (pub_key)
        ok = gost2001_do_verify(tbs, tbs_len, s, EVP_PKEY_get0(pub_key));
    DSA_SIG_free(s);
    return ok;
}

/* ------------- encrypt init -------------------------------------*/
/* Generates ephermeral key */
static int pkey_gost_encrypt_init(EVP_PKEY_CTX *ctx)
{
    return 1;
}

/* --------------- Derive init ------------------------------------*/
static int pkey_gost_derive_init(EVP_PKEY_CTX *ctx)
{
    return 1;
}

/* -------- PKEY_METHOD for GOST MAC algorithm --------------------*/
static int pkey_gost_mac_init(EVP_PKEY_CTX *ctx)
{
    struct gost_mac_pmeth_data *data = OPENSSL_zalloc(sizeof(*data));

    if (!data)
        return 0;
    EVP_PKEY_CTX_set_data(ctx, data);
    return 1;
}

static void pkey_gost_mac_cleanup(EVP_PKEY_CTX *ctx)
{
    struct gost_mac_pmeth_data *data = EVP_PKEY_CTX_get_data(ctx);
    OPENSSL_free(data);
}

static int pkey_gost_mac_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src)
{
    struct gost_mac_pmeth_data *dst_data, *src_data;
    if (!pkey_gost_mac_init(dst)) {
        return 0;
    }
    src_data = EVP_PKEY_CTX_get_data(src);
    dst_data = EVP_PKEY_CTX_get_data(dst);
    *dst_data = *src_data;
    return 1;
}

static int pkey_gost_mac_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
{
    struct gost_mac_pmeth_data *data =
        (struct gost_mac_pmeth_data *)EVP_PKEY_CTX_get_data(ctx);

    switch (type) {
    case EVP_PKEY_CTRL_MD:
        {
            if (EVP_MD_type((const EVP_MD *)p2) != NID_id_Gost28147_89_MAC) {
                GOSTerr(GOST_F_PKEY_GOST_MAC_CTRL,
                        GOST_R_INVALID_DIGEST_TYPE);
                return 0;
            }
            data->md = (EVP_MD *)p2;
            return 1;
        }

    case EVP_PKEY_CTRL_GET_MD:
        *(const EVP_MD **)p2 = data->md;
        return 1;

    case EVP_PKEY_CTRL_PKCS7_ENCRYPT:
    case EVP_PKEY_CTRL_PKCS7_DECRYPT:
    case EVP_PKEY_CTRL_PKCS7_SIGN:
        return 1;
    case EVP_PKEY_CTRL_SET_MAC_KEY:
        if (p1 != 32) {
            GOSTerr(GOST_F_PKEY_GOST_MAC_CTRL, GOST_R_INVALID_MAC_KEY_LENGTH);
            return 0;
        }

        memcpy(data->key, p2, 32);
        data->key_set = 1;
        return 1;
    case EVP_PKEY_CTRL_DIGESTINIT:
        {
            EVP_MD_CTX *mctx = p2;
            void *key;
            if (!data->key_set) {
                EVP_PKEY *pkey = EVP_PKEY_CTX_get0_pkey(ctx);
                if (!pkey) {
                    GOSTerr(GOST_F_PKEY_GOST_MAC_CTRL,
                            GOST_R_MAC_KEY_NOT_SET);
                    return 0;
                }
                key = EVP_PKEY_get0(pkey);
                if (!key) {
                    GOSTerr(GOST_F_PKEY_GOST_MAC_CTRL,
                            GOST_R_MAC_KEY_NOT_SET);
                    return 0;
                }
            } else {
                key = &(data->key);
            }
            return EVP_MD_meth_get_ctrl(EVP_MD_CTX_md(mctx))
                (mctx, EVP_MD_CTRL_SET_KEY, 32, key);
        }
    }
    return -2;
}

static int pkey_gost_mac_ctrl_str(EVP_PKEY_CTX *ctx,
                                  const char *type, const char *value)
{
    if (strcmp(type, key_ctrl_string) == 0) {
        if (strlen(value) != 32) {
            GOSTerr(GOST_F_PKEY_GOST_MAC_CTRL_STR,
                    GOST_R_INVALID_MAC_KEY_LENGTH);
            return 0;
        }
        return pkey_gost_mac_ctrl(ctx, EVP_PKEY_CTRL_SET_MAC_KEY,
                                  32, (char *)value);
    }
    if (strcmp(type, hexkey_ctrl_string) == 0) {
        long keylen;
        int ret;
        unsigned char *keybuf = string_to_hex(value, &keylen);
        if (!keybuf || keylen != 32) {
            GOSTerr(GOST_F_PKEY_GOST_MAC_CTRL_STR,
                    GOST_R_INVALID_MAC_KEY_LENGTH);
            OPENSSL_free(keybuf);
            return 0;
        }
        ret = pkey_gost_mac_ctrl(ctx, EVP_PKEY_CTRL_SET_MAC_KEY, 32, keybuf);
        OPENSSL_free(keybuf);
        return ret;

    }
    return -2;
}

static int pkey_gost_mac_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)
{
    struct gost_mac_pmeth_data *data = EVP_PKEY_CTX_get_data(ctx);
    unsigned char *keydata;
    if (!data->key_set) {
        GOSTerr(GOST_F_PKEY_GOST_MAC_KEYGEN, GOST_R_MAC_KEY_NOT_SET);
        return 0;
    }
    keydata = OPENSSL_malloc(32);
    if (keydata == NULL)
        return 0;
    memcpy(keydata, data->key, 32);
    EVP_PKEY_assign(pkey, NID_id_Gost28147_89_MAC, keydata);
    return 1;
}

static int pkey_gost_mac_signctx_init(EVP_PKEY_CTX *ctx, EVP_MD_CTX *mctx)
{
    return 1;
}

static int pkey_gost_mac_signctx(EVP_PKEY_CTX *ctx, unsigned char *sig,
                                 size_t *siglen, EVP_MD_CTX *mctx)
{
    unsigned int tmpsiglen = *siglen; /* for platforms where
                                       * sizeof(int)!=sizeof(size_t) */
    int ret;
    if (!sig) {
        *siglen = 4;
        return 1;
    }
    ret = EVP_DigestFinal_ex(mctx, sig, &tmpsiglen);
    *siglen = tmpsiglen;
    return ret;
}

/* ----------------------------------------------------------------*/
int register_pmeth_gost(int id, EVP_PKEY_METHOD **pmeth, int flags)
{
    *pmeth = EVP_PKEY_meth_new(id, flags);
    if (!*pmeth)
        return 0;

    switch (id) {
    case NID_id_GostR3410_2001:
        EVP_PKEY_meth_set_ctrl(*pmeth, pkey_gost_ctrl, pkey_gost_ctrl01_str);
        EVP_PKEY_meth_set_sign(*pmeth, NULL, pkey_gost01_cp_sign);
        EVP_PKEY_meth_set_verify(*pmeth, NULL, pkey_gost01_cp_verify);

        EVP_PKEY_meth_set_keygen(*pmeth, NULL, pkey_gost01cp_keygen);

        EVP_PKEY_meth_set_encrypt(*pmeth,
                                  pkey_gost_encrypt_init,
                                  pkey_GOST01cp_encrypt);
        EVP_PKEY_meth_set_decrypt(*pmeth, NULL, pkey_GOST01cp_decrypt);
        EVP_PKEY_meth_set_derive(*pmeth,
                                 pkey_gost_derive_init, pkey_gost2001_derive);
        EVP_PKEY_meth_set_paramgen(*pmeth, pkey_gost_paramgen_init,
                                   pkey_gost01_paramgen);
        break;
    case NID_id_Gost28147_89_MAC:
        EVP_PKEY_meth_set_ctrl(*pmeth, pkey_gost_mac_ctrl,
                               pkey_gost_mac_ctrl_str);
        EVP_PKEY_meth_set_signctx(*pmeth, pkey_gost_mac_signctx_init,
                                  pkey_gost_mac_signctx);
        EVP_PKEY_meth_set_keygen(*pmeth, NULL, pkey_gost_mac_keygen);
        EVP_PKEY_meth_set_init(*pmeth, pkey_gost_mac_init);
        EVP_PKEY_meth_set_cleanup(*pmeth, pkey_gost_mac_cleanup);
        EVP_PKEY_meth_set_copy(*pmeth, pkey_gost_mac_copy);
        return 1;
    default:                   /* Unsupported method */
        return 0;
    }
    EVP_PKEY_meth_set_init(*pmeth, pkey_gost_init);
    EVP_PKEY_meth_set_cleanup(*pmeth, pkey_gost_cleanup);

    EVP_PKEY_meth_set_copy(*pmeth, pkey_gost_copy);
    /*
     * FIXME derive etc...
     */

    return 1;
}
